NUCLEAR MATRIX ATTACHMENT REGIONS AND PLANT GENE-EXPRESSION

Higher-order chromatin organization is presumed to be mediated in part by DNA sequences that bind to the insoluble nuclear matrix. The funct ion of these 'matrix attachment regions' (MARs) has been investigated in transgenic plants. The studies indicated that MARs can reduce varia tion in, and increase, transgene expression levels, However, the hypot hesis that MARs fix chromatin loops to the nuclear matrix and insulate regulatory domains presently lacks firm confirmatory evidence, and al ternative models and experimental approaches need to be considered.